Propeller for flying-machines.



E. BERLlNE-R.

PROPELLER FOR FLYING MACHINES.

APPLICATION FILED MAR. 12. 1909.

1 ,1 90,092. Y Patented July 4, 1916.

Wi hwooeo EMILE BIEIBJlZ-Illl'EIt, OF WASHINGTON, DISTRICT OF COLUMBIA.

PROPELIIER FOR FLYING-MACHINES.

Specification of Letters Patent.

Patented July 4, 1916.

Application filed March 12 1909. Serial No. 483,034.

To all echo it may concern Be it known that I, Emma BERLINER, a

citizen of the United States, residing at.

\Vashington. in the District of Columbia, have invented certain new and useful Improvements in Propellers for Flying-Machines, of which the following is a description, reference being had to the accompanying drawing, and to the letters and figures of'reference marked thereon.

The invention relates to new and useful improvements in propeller blades, more especially adapted for flying machines, and said blade may be used to raise the machine into the air, to maintain the same in the air or to propel a machine of this character through the air.

The object of the invention is to provide a propeller in which the blade or blades are so shaped as to give greater efliciency; and more especially to increase the etliciency at slow speeds without sacrificing the maximum etliciency of the propeller when driven at a high speed.

The invention consists in the parts hereinafter shown, described and pointed out in the appended claims.

In the drawing Figure 1 is a side elevation of the propeller; Fig. .2 is-a plan view of the face of the propeller; Fig. 3 is an end view of the blades of the propeller; and

Fig. 4 is a sectional view through one of the blades on the line lof Fig. 2.

In the drawings, the hub of the propeller 1 is of the usual construction, and is shown as provided with two radial blades 2 and It will be understood, of course, that any number of blades may be used, and that my invention is not in any way limited to the number of blades, the construction of the hub, or the particular manner of support ing the blades by the hubs, as these features are of the usual construction in propellers of this type.

The propeller blade, as herein shown, is substantially triangular in outline, and is attached to the hub so that said blade tapers toward the hub. The propeller blade 15 attached to the hub, so that the main por-' tion of the blade lies in a plane indicated by the line a:w, Fig. 3, which cuts the axis of the hub, indicated by the line 3 g at an tlt'nlie angle. The propeller. blade at the p- .int 5 is curved gradually toward the face 0 the blade 6, an to such an extent that a cross section through the blade (see Fig. at), is substantially shaped like a longitudinal section through the wing of a bird.

As herein. shown, the front or cutting edge is so curved that a plane tangential to .said curve at the edge thereof, as indicated by theline Fig. 3, cuts the axis of the hub y-y, at an angle which is substantially the supplement of the acute angle formed by the plane containing the body of the blade, and cutting the axis of. the hub.

It will be noted that the curvature of the blade extends substantially throughout the entire length of the blade. The direction of the rotation of the propeller is indicated by the arrow in Figs. 2 andg-l,

It will be seen that my propeller blade is so shaped that the front or cutting edge is curved toward the face of the blade, and by this construction I have found that the etliciency of the blade when driven at slow speeds, is greatly increased, while the maximum etticiency of the blade when driven at a high speed, is not in any way sacrificed.

Having thus described my invention. what I claim as new and desire to secure by Let'- ters Patent, is

l. A propeller for flying machines includ ing a hub, a blade projecting from said hub, said blade being substantially triangular in outlinewith its front or cutting edge from the hub to the tip thereof offset from the plane of the body of the blade and part of the blade adjacent the offset cutting edge being formed on a shallow curve merging into the plane of the blade.

52. A propeller for flying machines, including a hub, a blade projecting from said hub. said blade being substantially of uniform thickness and substantially triangular in outline with its front or cutting edge from the hub to the tip thereof curved and offset from the plane of the body of the blade whereby a plane tangential to said curve at the edge thereof cuts the axis of the hub at an acute angle which is substantially the'supplement of the angle formed by the plane containing the body of the blade and cutting the axis of the hub.

In testimony whereof I atlix my signa ture, in presence of two witnesses.

EMILE BER-LINER. lVitnesses IIOLLAND H. KNoTTs, E. B. SHAYER. 

